Every year, nearly 800,000 Americans endure a first myocardial infarction (MI), and over half of those will have a recurrent event. There are numerous factors that influence prognosis following an MI. In addition to physical factors, such as initial MI severity and adherence to medication and cardiac rehabilitation programs, psychosocial factors are highly predictive of future clinical course. Positive affect, finding meaning in the MI event, and in life in general, and managing the consequences and emotional distress of the MI are highly important. Gratitude is typically defined as a feeling or attitude in acknowledgment of a benefit that one has received or will receive, a habitual focusing on and appreciating the positive aspects of life. It is associated with higher levels of subjective well-being, and people who are more grateful experience less stress, are less depressed, have higher levels of control over their environment, have more positive ways of coping with life's difficulties, and have fewer negative coping strategies. Gratitude is correlated with self-reported physical health, and this link is mediated by psychological health, healthy activities, and willingness to seek help for health. Interventions to clinically increase gratitude have shown great promise, demonstrating the ability to increase overall sense of well-being, meaning in life, and potential associations with improved health. In 113 patients within 30 days of a first-time MI, this proposed exploratory intervention study will examine whether an eight-week gratitude journaling intervention coupled with standard of care (SOC), as compared to SOC plus journaling memorable events and SOC alone will increase positive health behaviors, psychological health, and physical functioning. Psychosocial and clinical assessments will be performed over a six-month period, with testing occurring before, immediately after, and four months after treatment. We envision the study's findings will (a) scientifically show evidence of causality in the relationship between gratitude and our clinically relevant endpoints, (b) therapeutically provide a new intervention methodology to harness these benefits in this cardiac population, and (c) show mechanisms that underlie both the natural and therapeutic effects, both to improve scientific understanding and to allow more tailored interventions to be developed at a later date.